Methods and apparatus to stimulate the heart
A method and apparatus for treatment of hypertension and heart failure by increasing secretion of endogenous atrial hormones by pacing of the heart. Pacing is done during the ventricular refractory period resulting in premature atrial contraction that does not result in ventricular contraction. Pacing results in the atrial wall stress, peripheral vasodilation, ANP secretion. Concomitant reduction of the heart rate is monitored and controlled as needed with backup pacing.
1. A device for controlling heart contraction to reduce blood pressure, the device comprising:
at least one electrically conductive lead configured to connect to a heart of a patient;
an electrical pulse generator connectable to the at least one electrically conductive lead and configured to:
apply to an atrium of the heart a first atrial pacing upon expiration of a predetermined delay following an atrial refractory period of the heart and during a ventricular refractory period of the heart,
monitor a heart rate of the patient in conjunction with applying the first atrial pacing, and
apply a second atrial pacing to the atrium if the monitored heart rate is less than a predetermined minimum heart rate.
2. The device of claim 1 , wherein the electrical pulse generator is configured to reduce the predetermined delay in response to a detection of propagation of the first atrial pacing to a ventricle of the heart.
3. The device of claim 1 , wherein the electrical pulse generator is configured to periodically increase the predetermined delay to coincide with an expiration of the ventricular refractory period.
4. The device of claim 3 , wherein the electrical pulse generator is configured to set a time of the second atrial pacing to a time less than the expiration of the ventricular refractory period.
5. The device of claim 1 , wherein the electric pulse generator is configured to suspend application of the first atrial pacing and the second atrial pacing in response to a detected activity level of the patient that is above a predetermined threshold level.
6. The device of claim 5 , further comprising an activity sensor configured to detect the activity level of the patient.
7. The device of claim 1 , wherein the electrical pulse generator is configured to apply the first atrial pacing in response to a sensed ventricular depolarization of the heart.
8. The device of claim 7 , further comprising a sensor configured to sense the ventricular depolarization of the heart.
9. The device of claim 1 , wherein the electrical pulse generator is configured to apply the first atrial pacing upon expiration of a predetermined delay from a sensed ventricular depolarization of the heart.
10. The device of claim 9 , further comprising a sensor configured to sense the ventricular depolarization of the heart.
11. The device of claim 1 , wherein the electrical pulse generator is configured to apply the first atrial pacing based on a sensed atrial depolarization of the heart.
12. The device of claim 11 , further comprising a sensor configured to sense the atrial depolarization of the heart.
13. The device of claim 1 , wherein the electrical pulse generator is configured to apply the first atrial pacing between approximately 150 milliseconds and 300 milliseconds after a sensed first ventricular contraction.
14. The device of claim 13 , further comprising a sensor configured to sense the first ventricular contraction of a ventricle of the heart.
15. The device of claim 1 , wherein the atrium comprises one of a left atrium or a right atrium.
16. The device of claim 1 , wherein the predetermined minimum heart rate is less than approximately 50 beats per minute.